Correlation between Mw and R in set of records used. For 4.5 ≤ Mw≤ 5.0 records exist at R ≤ 40km
and for larger magnitudes records exist at intermediate and long distances. For Mw> 6.0 there is a lack
of records for R < 20km.

Use a two step regression method. In first step use all records to find c1. In second step use records from
earthquakes with Mw≥ 5.0 to find c0, c2 and c3.

Adopt R0= 6km because difficult to find R0 via regression due to its strong correlation with c2. This
corresponds to average focal depth of earthquakes used.